Merge remote-tracking branch 'pm/linux-next'
[linux-2.6/next.git] / drivers / base / memory.c
blob2840ed4668c1e234590be4c253d36e8d29e87ab8
1 /*
2 * drivers/base/memory.c - basic Memory class support
4 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
5 * Dave Hansen <haveblue@us.ibm.com>
7 * This file provides the necessary infrastructure to represent
8 * a SPARSEMEM-memory-model system's physical memory in /sysfs.
9 * All arch-independent code that assumes MEMORY_HOTPLUG requires
10 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
13 #include <linux/sysdev.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/topology.h>
17 #include <linux/capability.h>
18 #include <linux/device.h>
19 #include <linux/memory.h>
20 #include <linux/kobject.h>
21 #include <linux/memory_hotplug.h>
22 #include <linux/mm.h>
23 #include <linux/mutex.h>
24 #include <linux/stat.h>
25 #include <linux/slab.h>
27 #include <linux/atomic.h>
28 #include <asm/uaccess.h>
30 static DEFINE_MUTEX(mem_sysfs_mutex);
32 #define MEMORY_CLASS_NAME "memory"
34 static int sections_per_block;
36 static inline int base_memory_block_id(int section_nr)
38 return section_nr / sections_per_block;
41 static struct sysdev_class memory_sysdev_class = {
42 .name = MEMORY_CLASS_NAME,
45 static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)
47 return MEMORY_CLASS_NAME;
50 static int memory_uevent(struct kset *kset, struct kobject *obj,
51 struct kobj_uevent_env *env)
53 int retval = 0;
55 return retval;
58 static const struct kset_uevent_ops memory_uevent_ops = {
59 .name = memory_uevent_name,
60 .uevent = memory_uevent,
63 static BLOCKING_NOTIFIER_HEAD(memory_chain);
65 int register_memory_notifier(struct notifier_block *nb)
67 return blocking_notifier_chain_register(&memory_chain, nb);
69 EXPORT_SYMBOL(register_memory_notifier);
71 void unregister_memory_notifier(struct notifier_block *nb)
73 blocking_notifier_chain_unregister(&memory_chain, nb);
75 EXPORT_SYMBOL(unregister_memory_notifier);
77 static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
79 int register_memory_isolate_notifier(struct notifier_block *nb)
81 return atomic_notifier_chain_register(&memory_isolate_chain, nb);
83 EXPORT_SYMBOL(register_memory_isolate_notifier);
85 void unregister_memory_isolate_notifier(struct notifier_block *nb)
87 atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
89 EXPORT_SYMBOL(unregister_memory_isolate_notifier);
92 * register_memory - Setup a sysfs device for a memory block
94 static
95 int register_memory(struct memory_block *memory)
97 int error;
99 memory->sysdev.cls = &memory_sysdev_class;
100 memory->sysdev.id = memory->start_section_nr / sections_per_block;
102 error = sysdev_register(&memory->sysdev);
103 return error;
106 static void
107 unregister_memory(struct memory_block *memory)
109 BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
111 /* drop the ref. we got in remove_memory_block() */
112 kobject_put(&memory->sysdev.kobj);
113 sysdev_unregister(&memory->sysdev);
116 unsigned long __weak memory_block_size_bytes(void)
118 return MIN_MEMORY_BLOCK_SIZE;
121 static unsigned long get_memory_block_size(void)
123 unsigned long block_sz;
125 block_sz = memory_block_size_bytes();
127 /* Validate blk_sz is a power of 2 and not less than section size */
128 if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
129 WARN_ON(1);
130 block_sz = MIN_MEMORY_BLOCK_SIZE;
133 return block_sz;
137 * use this as the physical section index that this memsection
138 * uses.
141 static ssize_t show_mem_start_phys_index(struct sys_device *dev,
142 struct sysdev_attribute *attr, char *buf)
144 struct memory_block *mem =
145 container_of(dev, struct memory_block, sysdev);
146 unsigned long phys_index;
148 phys_index = mem->start_section_nr / sections_per_block;
149 return sprintf(buf, "%08lx\n", phys_index);
152 static ssize_t show_mem_end_phys_index(struct sys_device *dev,
153 struct sysdev_attribute *attr, char *buf)
155 struct memory_block *mem =
156 container_of(dev, struct memory_block, sysdev);
157 unsigned long phys_index;
159 phys_index = mem->end_section_nr / sections_per_block;
160 return sprintf(buf, "%08lx\n", phys_index);
164 * Show whether the section of memory is likely to be hot-removable
166 static ssize_t show_mem_removable(struct sys_device *dev,
167 struct sysdev_attribute *attr, char *buf)
169 unsigned long i, pfn;
170 int ret = 1;
171 struct memory_block *mem =
172 container_of(dev, struct memory_block, sysdev);
174 for (i = 0; i < sections_per_block; i++) {
175 pfn = section_nr_to_pfn(mem->start_section_nr + i);
176 ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
179 return sprintf(buf, "%d\n", ret);
183 * online, offline, going offline, etc.
185 static ssize_t show_mem_state(struct sys_device *dev,
186 struct sysdev_attribute *attr, char *buf)
188 struct memory_block *mem =
189 container_of(dev, struct memory_block, sysdev);
190 ssize_t len = 0;
193 * We can probably put these states in a nice little array
194 * so that they're not open-coded
196 switch (mem->state) {
197 case MEM_ONLINE:
198 len = sprintf(buf, "online\n");
199 break;
200 case MEM_OFFLINE:
201 len = sprintf(buf, "offline\n");
202 break;
203 case MEM_GOING_OFFLINE:
204 len = sprintf(buf, "going-offline\n");
205 break;
206 default:
207 len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
208 mem->state);
209 WARN_ON(1);
210 break;
213 return len;
216 int memory_notify(unsigned long val, void *v)
218 return blocking_notifier_call_chain(&memory_chain, val, v);
221 int memory_isolate_notify(unsigned long val, void *v)
223 return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
227 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
228 * OK to have direct references to sparsemem variables in here.
230 static int
231 memory_block_action(unsigned long phys_index, unsigned long action)
233 int i;
234 unsigned long start_pfn, start_paddr;
235 unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
236 struct page *first_page;
237 int ret;
239 first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
242 * The probe routines leave the pages reserved, just
243 * as the bootmem code does. Make sure they're still
244 * that way.
246 if (action == MEM_ONLINE) {
247 for (i = 0; i < nr_pages; i++) {
248 if (PageReserved(first_page+i))
249 continue;
251 printk(KERN_WARNING "section number %ld page number %d "
252 "not reserved, was it already online?\n",
253 phys_index, i);
254 return -EBUSY;
258 switch (action) {
259 case MEM_ONLINE:
260 start_pfn = page_to_pfn(first_page);
261 ret = online_pages(start_pfn, nr_pages);
262 break;
263 case MEM_OFFLINE:
264 start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
265 ret = remove_memory(start_paddr,
266 nr_pages << PAGE_SHIFT);
267 break;
268 default:
269 WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
270 "%ld\n", __func__, phys_index, action, action);
271 ret = -EINVAL;
274 return ret;
277 static int memory_block_change_state(struct memory_block *mem,
278 unsigned long to_state, unsigned long from_state_req)
280 int ret = 0;
282 mutex_lock(&mem->state_mutex);
284 if (mem->state != from_state_req) {
285 ret = -EINVAL;
286 goto out;
289 if (to_state == MEM_OFFLINE)
290 mem->state = MEM_GOING_OFFLINE;
292 ret = memory_block_action(mem->start_section_nr, to_state);
294 if (ret)
295 mem->state = from_state_req;
296 else
297 mem->state = to_state;
299 out:
300 mutex_unlock(&mem->state_mutex);
301 return ret;
304 static ssize_t
305 store_mem_state(struct sys_device *dev,
306 struct sysdev_attribute *attr, const char *buf, size_t count)
308 struct memory_block *mem;
309 int ret = -EINVAL;
311 mem = container_of(dev, struct memory_block, sysdev);
313 if (!strncmp(buf, "online", min((int)count, 6)))
314 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
315 else if(!strncmp(buf, "offline", min((int)count, 7)))
316 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
318 if (ret)
319 return ret;
320 return count;
324 * phys_device is a bad name for this. What I really want
325 * is a way to differentiate between memory ranges that
326 * are part of physical devices that constitute
327 * a complete removable unit or fru.
328 * i.e. do these ranges belong to the same physical device,
329 * s.t. if I offline all of these sections I can then
330 * remove the physical device?
332 static ssize_t show_phys_device(struct sys_device *dev,
333 struct sysdev_attribute *attr, char *buf)
335 struct memory_block *mem =
336 container_of(dev, struct memory_block, sysdev);
337 return sprintf(buf, "%d\n", mem->phys_device);
340 static SYSDEV_ATTR(phys_index, 0444, show_mem_start_phys_index, NULL);
341 static SYSDEV_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
342 static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
343 static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
344 static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
346 #define mem_create_simple_file(mem, attr_name) \
347 sysdev_create_file(&mem->sysdev, &attr_##attr_name)
348 #define mem_remove_simple_file(mem, attr_name) \
349 sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
352 * Block size attribute stuff
354 static ssize_t
355 print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,
356 char *buf)
358 return sprintf(buf, "%lx\n", get_memory_block_size());
361 static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
363 static int block_size_init(void)
365 return sysfs_create_file(&memory_sysdev_class.kset.kobj,
366 &attr_block_size_bytes.attr);
370 * Some architectures will have custom drivers to do this, and
371 * will not need to do it from userspace. The fake hot-add code
372 * as well as ppc64 will do all of their discovery in userspace
373 * and will require this interface.
375 #ifdef CONFIG_ARCH_MEMORY_PROBE
376 static ssize_t
377 memory_probe_store(struct class *class, struct class_attribute *attr,
378 const char *buf, size_t count)
380 u64 phys_addr;
381 int nid;
382 int i, ret;
384 phys_addr = simple_strtoull(buf, NULL, 0);
386 for (i = 0; i < sections_per_block; i++) {
387 nid = memory_add_physaddr_to_nid(phys_addr);
388 ret = add_memory(nid, phys_addr,
389 PAGES_PER_SECTION << PAGE_SHIFT);
390 if (ret)
391 goto out;
393 phys_addr += MIN_MEMORY_BLOCK_SIZE;
396 ret = count;
397 out:
398 return ret;
400 static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
402 static int memory_probe_init(void)
404 return sysfs_create_file(&memory_sysdev_class.kset.kobj,
405 &class_attr_probe.attr);
407 #else
408 static inline int memory_probe_init(void)
410 return 0;
412 #endif
414 #ifdef CONFIG_MEMORY_FAILURE
416 * Support for offlining pages of memory
419 /* Soft offline a page */
420 static ssize_t
421 store_soft_offline_page(struct class *class,
422 struct class_attribute *attr,
423 const char *buf, size_t count)
425 int ret;
426 u64 pfn;
427 if (!capable(CAP_SYS_ADMIN))
428 return -EPERM;
429 if (strict_strtoull(buf, 0, &pfn) < 0)
430 return -EINVAL;
431 pfn >>= PAGE_SHIFT;
432 if (!pfn_valid(pfn))
433 return -ENXIO;
434 ret = soft_offline_page(pfn_to_page(pfn), 0);
435 return ret == 0 ? count : ret;
438 /* Forcibly offline a page, including killing processes. */
439 static ssize_t
440 store_hard_offline_page(struct class *class,
441 struct class_attribute *attr,
442 const char *buf, size_t count)
444 int ret;
445 u64 pfn;
446 if (!capable(CAP_SYS_ADMIN))
447 return -EPERM;
448 if (strict_strtoull(buf, 0, &pfn) < 0)
449 return -EINVAL;
450 pfn >>= PAGE_SHIFT;
451 ret = __memory_failure(pfn, 0, 0);
452 return ret ? ret : count;
455 static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
456 static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
458 static __init int memory_fail_init(void)
460 int err;
462 err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
463 &class_attr_soft_offline_page.attr);
464 if (!err)
465 err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
466 &class_attr_hard_offline_page.attr);
467 return err;
469 #else
470 static inline int memory_fail_init(void)
472 return 0;
474 #endif
477 * Note that phys_device is optional. It is here to allow for
478 * differentiation between which *physical* devices each
479 * section belongs to...
481 int __weak arch_get_memory_phys_device(unsigned long start_pfn)
483 return 0;
486 struct memory_block *find_memory_block_hinted(struct mem_section *section,
487 struct memory_block *hint)
489 struct kobject *kobj;
490 struct sys_device *sysdev;
491 struct memory_block *mem;
492 char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
493 int block_id = base_memory_block_id(__section_nr(section));
495 kobj = hint ? &hint->sysdev.kobj : NULL;
498 * This only works because we know that section == sysdev->id
499 * slightly redundant with sysdev_register()
501 sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, block_id);
503 kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
504 if (!kobj)
505 return NULL;
507 sysdev = container_of(kobj, struct sys_device, kobj);
508 mem = container_of(sysdev, struct memory_block, sysdev);
510 return mem;
514 * For now, we have a linear search to go find the appropriate
515 * memory_block corresponding to a particular phys_index. If
516 * this gets to be a real problem, we can always use a radix
517 * tree or something here.
519 * This could be made generic for all sysdev classes.
521 struct memory_block *find_memory_block(struct mem_section *section)
523 return find_memory_block_hinted(section, NULL);
526 static int init_memory_block(struct memory_block **memory,
527 struct mem_section *section, unsigned long state)
529 struct memory_block *mem;
530 unsigned long start_pfn;
531 int scn_nr;
532 int ret = 0;
534 mem = kzalloc(sizeof(*mem), GFP_KERNEL);
535 if (!mem)
536 return -ENOMEM;
538 scn_nr = __section_nr(section);
539 mem->start_section_nr =
540 base_memory_block_id(scn_nr) * sections_per_block;
541 mem->end_section_nr = mem->start_section_nr + sections_per_block - 1;
542 mem->state = state;
543 mem->section_count++;
544 mutex_init(&mem->state_mutex);
545 start_pfn = section_nr_to_pfn(mem->start_section_nr);
546 mem->phys_device = arch_get_memory_phys_device(start_pfn);
548 ret = register_memory(mem);
549 if (!ret)
550 ret = mem_create_simple_file(mem, phys_index);
551 if (!ret)
552 ret = mem_create_simple_file(mem, end_phys_index);
553 if (!ret)
554 ret = mem_create_simple_file(mem, state);
555 if (!ret)
556 ret = mem_create_simple_file(mem, phys_device);
557 if (!ret)
558 ret = mem_create_simple_file(mem, removable);
560 *memory = mem;
561 return ret;
564 static int add_memory_section(int nid, struct mem_section *section,
565 unsigned long state, enum mem_add_context context)
567 struct memory_block *mem;
568 int ret = 0;
570 mutex_lock(&mem_sysfs_mutex);
572 mem = find_memory_block(section);
573 if (mem) {
574 mem->section_count++;
575 kobject_put(&mem->sysdev.kobj);
576 } else
577 ret = init_memory_block(&mem, section, state);
579 if (!ret) {
580 if (context == HOTPLUG &&
581 mem->section_count == sections_per_block)
582 ret = register_mem_sect_under_node(mem, nid);
585 mutex_unlock(&mem_sysfs_mutex);
586 return ret;
589 int remove_memory_block(unsigned long node_id, struct mem_section *section,
590 int phys_device)
592 struct memory_block *mem;
594 mutex_lock(&mem_sysfs_mutex);
595 mem = find_memory_block(section);
596 unregister_mem_sect_under_nodes(mem, __section_nr(section));
598 mem->section_count--;
599 if (mem->section_count == 0) {
600 mem_remove_simple_file(mem, phys_index);
601 mem_remove_simple_file(mem, end_phys_index);
602 mem_remove_simple_file(mem, state);
603 mem_remove_simple_file(mem, phys_device);
604 mem_remove_simple_file(mem, removable);
605 unregister_memory(mem);
606 kfree(mem);
607 } else
608 kobject_put(&mem->sysdev.kobj);
610 mutex_unlock(&mem_sysfs_mutex);
611 return 0;
615 * need an interface for the VM to add new memory regions,
616 * but without onlining it.
618 int register_new_memory(int nid, struct mem_section *section)
620 return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
623 int unregister_memory_section(struct mem_section *section)
625 if (!present_section(section))
626 return -EINVAL;
628 return remove_memory_block(0, section, 0);
632 * Initialize the sysfs support for memory devices...
634 int __init memory_dev_init(void)
636 unsigned int i;
637 int ret;
638 int err;
639 unsigned long block_sz;
641 memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
642 ret = sysdev_class_register(&memory_sysdev_class);
643 if (ret)
644 goto out;
646 block_sz = get_memory_block_size();
647 sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
650 * Create entries for memory sections that were found
651 * during boot and have been initialized
653 for (i = 0; i < NR_MEM_SECTIONS; i++) {
654 if (!present_section_nr(i))
655 continue;
656 err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
657 BOOT);
658 if (!ret)
659 ret = err;
662 err = memory_probe_init();
663 if (!ret)
664 ret = err;
665 err = memory_fail_init();
666 if (!ret)
667 ret = err;
668 err = block_size_init();
669 if (!ret)
670 ret = err;
671 out:
672 if (ret)
673 printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
674 return ret;